Estradiol upregulates Kiss1 expression in the medial tuberal nucleus in mice.

STEPHENS SBZ ; LUX LANTOS VAR; LIAW RB; KAUFFMAN AS; DI GIORGIO NP

San Diego

Congreso; Annual Meeting of Society for Neuroscience (SFN); 2018

Society for Neuroscience

Kisspeptin, encoded by Kiss1, stimulates GnRH release and is required for reproduction. Kiss1 neurons reside in the hypothalamic AVPV/PeN and ARC nuclei, and in smaller numbers in extra-hypothalamic areas, including the medial amygdala, bed nucleus of the stria terminalis, and lateral septum. Recently, a small population of Kiss1 neurons in the lateral hypothalamic region was newly identified in sheep. We identified a similar small population of Kiss1 neurons in this general region in mice, specifically in the medial tuberal nucleus (MTu) of the hypothalamus. In adult Kiss1-Cre TdTomato+ mice, a small population of TdTomato-expressing cells were found in the MTu of both male and female mice. A small population of Kiss1mRNA-expressing cells was also detected, using in situ hybridization, in the MTu of adult male mice. Nothing is currently known about the regulation and function of Kiss1neurons in the MTu, though estradiol (E2) strongly upregulates Kiss1 expression in the AVPV/PeN, MeA, and BnST but downregulates Kiss1 expression in the ARC. Because all previously-identifiedKiss1neural populations are regulated by estradiol and ERα, ERβ, and aromatase are expressed in the MTu, we hypothesized that Kiss1 in the MTu is also regulated by E2. Using in situ hybridization, we found that gonadectomized male and female mice had essentially no detectable Kiss1 expression in the MTu. By comparison, E2 treatment significantly increased Kiss1 expression in the MTu of both sexes. Thus, like the AVPV and extra-hypothalamic Kiss1 neuronal populations, Kiss1 expression in the MTu is upregulated by E2. Additional research is needed to further characterize the regulation andpotential functions of this small population of newly identified Kiss1 neurons in the MTu.